Lightweight concrete and process of making the same



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Patented Apr. 30, 1929. i i W5 UNITED STATES PATENT FFICE.

ROY CROSS, OF KANSAS CITY, MISSOURI, AND WILLIAM A. COLLINGS, OF SANTA MONICA, CALIFORNIA, ASSIGNORS T0 SILICA PRODUCTS CO., OF LOS ANGELES, CALIFORNIA, A CORPORATION OF DELAWARE.

LIGHTWEIGHT CONCRETE AND PROCESS OF MAKING THE SAME.

No Drawing. Application filed March 25, 1925. Serial No. 18,308.

This invention relates to a composition of cific gravity. Broadly, the mix contains h matter anda process of making the same, and draulic cement with a fine or coarse 511% 55 refers more particularly to the production e to a aggregate including the echo en? of a plastic or molding building material welghmg, on a dry basis, not more than 130 5 which may be used in the form of a plaster pounds or less than 80 pounds per cubic foot or mortar andmay be molded intoblocks,tiles, as distinguished from a calcareous sand agbricks or set in forms in the making of unigregate weighing from 140 to 160 poundspenm tary walls, floors, roads or innumerable other cubic foot on a dry basis. There is no segretypes of building construction. ga-tlon of the materials in the raw mix which The application is a continuation in part may carry from 8% to of water.

of a prior application filed in the name of While 1t is recognized that cinder blocks William A. Collings,Serial No. 680,044 dated constitute a very valuable material for the December 11th, 1923. above named purposes, they have the disad- The advantages of this material lie privantages that they are still relativel heavy 15 marily in its waterproof qualities and its and that they are porous to waljer Fiifiojfl li htness of wei ht as compared with the the size an arg e percentage 0 voids, are

usual concrete or m1x used in buildin gonsu5 ect to dlsmtegration by the action of sulstruction; also, its smoot ness and lasticity phur, -and cause corrosion with nails or other maEmg-it easy to worl: and lts uniform texmetals with which they come in contact.

20 ture du to the fact that the ingredients are The particular quality of being capable of evenly distributed through the mass or aggreholdlng nails can verv much improved y gate and remain so while setting, avoiding the present invention as itgives the block or the difliculties of segregation so common in llillllfi more uniform and compact charconnection with a mixture of this sort where acter. lne present invention, furthermore,

25 a light filler is used which has a relatively water-proofing the blocks, tiles or walls, prelighter specific gravity than the matrix and vents COII'OSlOIl of metals in contact with them the other materials of the mix. at the same time retaining the lightness of While the waterproofing substance and weight. ThlS result is accomplished in the leavening products may as well and as efi'ecpresent invention by thin-IMM- 30 tively be used with the usual type of concrete nary block mixture or aggregate mixture of having a cement matrix with a calcareous a gelatinous cla or h drous aluminum i1- and sand base or filler. It is thought that 921W PHCHLH'I'OCIVltlQSOfswt-fllthis phase of the invention is satisfactorily mg with the at dition or presence of water. covered in the prior application referred to, Sucfimateria] is a hydrous aluminum sili- 35 while the present invention lies particularly cate found naturally in some of the Western in the use of a lighter filler material such as States-sueh as Wyoming and California cinders and clay or ceramic products heated and commonly known as bentonite. Other to intumescence. This plastic composition clays of similar character, having the characfor building construction is admirably teristic of swelling with water, may as well 40 adapted for use in the place of concrete or be used, as the essential quality is to fill the cinder blocks which are extensively used in voids of the mix with the addition of moisreplacing brick and stone in basement walls, turgprcventmg the seepin g of water or 11151? fire walls, curtain walls and similar constructurc through the Monks or wall after the contions. The material has the required strength crcte or mix has set. It is desirable, and of 45 for bein formed into outside walls aTdfhe importance, combine the water roofin mm-WW1 c l a w1th the lIllX whlle the former is 1n 1nt1- WICEJQII. Ms mentioned, too, it may be mate contact with an oil, such as kerosene mixed as an aggregate and set in forms simi- "as oil s i dle oils crude oil or oth e'rTi q'fi'i'd' larly to the ordinary concrete mix due to the capable of preventing the lmmediate water 50 fact that it has the quality of maintaining the contact. At this point, attention is called to ingredients uniformly distributed therethe fact that this waterproofing material is through without separation or segregation of not used as a retar'dent to dry or retard the 10.5 the water and the substances of different spesetting of the concrete or mix, It is desir:

' 30 to a-bou able to combine with the gelatinous cla such as bentonite and oil, a'pei'centage of diatomaceous earth which has a leavening efiegt upon the mix. A typical method of manu- 5 facture would be the following: To one part of air dried bentonite or "elatinoh's c'a 1s a ce wo pa y welght. Th1s 1s nnxe 1nc1p1en astlc- Whg intumescepgg.

2 er and the coarse er are now put in a mixer andme and diatomaceous earth are added. lVhile the mixer 1s running, suflicient water is added to ive the right )lasticitv. ilrdmarlly, this amounts 5 /0 by weight. lVhen maximum density is not required, the oil or naphtha is not used. It will be found that this mixture has a very good plasticity and that the water does not segregate from the wet mix due,

perhaps, to the qualities of the gelatinous clay of maintaining the ingredients in a relatively permanent suspension. The wet mix, when placed in a form, requires very little working and on account of the large amount of water carried, the desired lightness of weight is obtained. At the same time, on account of the bentonite or gelatinous clay, the mixture is more uniform in texture, of greater density, and the voids more complete- 1y filled,g1ving an excellent average strength. As described. the diatomaceous earth has the characteristic of adding leavening qualities to the mix.

Using cinders or shale or clay treated to intumescence for making concrete is not. new, but heretofore it has not been possible to attain a good plasticity and prevent separation of the water and aggregate due to the wide range of specific gravities of their ingredients and their peculiar adverse tendencies to combine. Furthermore, in the manufacture of the tiles, blocks or aggregate for unitary structures by mix explained in the presentinvention, little working .or tamping in necessary, as the plasticity and void filling qualities are exceptionally good. Furthermore, reenforcement, such as strands of wire, metal lath or other rigid or semi-rigid reenforcement, can be incorporated without diflic5 culties and can be easily kept in place. Metal reenforcement does not corrode on account of the waterproofing qualities of the mlx. Further, the concrete or mixture has the waterproofing qualities due to the fact that the bentonite or swelling clay when it comes in contact with the water quickly enlarges, filling the voids of the structure and preventing further ingress of the moisture. The use of an oil in combining the waterproofing material with the mix is important as it allows the incorporation of a larger amount of the gelatinous clay, thus temporarily waterproofing it. As described, the temporary waterproofing of the clay is to prevent contact of the clay and water during gaging of the concrete, at which time the usual proportions of water are employed, that is, a sufiicient amount of water required for hydration of the cement.

It will be noted that throughout the application the word concrete has been used to denote merely a mix or a mixture of the ingredients mentioned, as distinguished from the common use of concrete in the cement industry where it applies primarily to a, cement containing calcareous material.

The particular character of the mix which differentiates it from a concrete or mix of similar nature and made up of similar in-' gredients, is the feature which is most clearly brought out by the slump test adopted by the American Society of Testing Materials in 1922 and described on pages 398 and 399 of the 1924 A. S. T. M. Tentative Standards. This test is a method of determining the consistency of Portland cement concrete which is ascertained by the tendency of a mass of such a material to slump from its original form. The material such as described in the present invention has a slump test of not more than 4 inches according to this standard, nor is there any appreciable segregation of water or draining off of the water attending this test. The slump test can be controlled by the amount of gelatinous clay for very wide ranges of water content. A gelatinous clay of this character, capable of taking up large amounts of'water, forms a production which is not only light of weight when dried in a hardened condition, but is easily worked when in a plastic condition due to the presence of this water.

\Vith regard to the relative amounts of water as compared to the amount of waterproofing material used, normally the amount of water present relative that of waterproofing material is as 20 1. Although such relation is typical, a range of from 30: 1 or less is included within the scope of the invention. This range also depends upon the properties of the gelatinous clay used.

In addition to the light aggregates or fillers heretofore referred to, namely, cinders and clay heated to intumescence, a number of other materials such as natural light matememos? COATING R PLASTIC.

'Tt'is recognized, further, that diatomaeeous "earths when used alone have the characteristic of swelling slightly with additions of water and may have to a less extent the waterproofing properties of the bentonite or gelatinous adsorptive clay materials mentioned. For this reason, they may be used alone for the purposes mentioned in connection with the clay, but are nor nally not assatisfactory due to the fact that they are incapable of filling up the voids as completely as the clay material.

\Ve claim as our invention:

1. A batch for concrete capable of being poured, made of a hydraulic matrix, mineral filler and a gelatinizing clay adapted to expand when brought in contact with moisture, and to hold the aggregate in suspension in the water vehicle, said mix weighing in the air dried condition between 85 and 130 pounds per cubic foot.

2. A batch for concrete capable of being poured, made of a hydraulic matrix, mineral filler and a gelatinizing clay adapted to expand when brought in contact with moisture, and to hold the aggregate in suspension in the water vehicle, said mix weighing in the air dried condition between 85 and 130 pounds per cubic foot and absorbing not more than 5% water after hydration and setting of the mix.

3. A composition of matter for building purposes containing a hydraulic cement matrix, fine and coarse filler, weighing on a dry basis not more than 130 pounds or less than 80 pounds per cubic foot and a gelatinizing clay capable of preventing the ingress of moisture and separation of the aggregate from. the water vehicle.

ROY CROSS. WILLIAM A. COLLIN GS.

Examine; 

